engine sounds are the safest. Your gonna get plowed into when someone yells at you to move and you do the moon walk instead of turning.

 

I would never be able to do it. I listin to the sound of the motor when im driving..I think It would be hard to judge what gear you need without hearing it...I jsut got used to doing it by ear and it would be hard to do other wise. Plus i don't think it would be too safe because you wouldn't hear other people either.